PYTHON script using OS commands to start ONOS controller, RYU Controller and add ISP router flows? (GNS3)

Question

Within a UBUNTU VM, using GNS3 I created code that is an attempt to perform 3 different outcomes, since these programs can't run mutally in the same terminal however I'm not sure how to seperate them into seperate terminals and add delays inbetween to prevent any issues that might occur.

 #!/usr/bin/python3
 import os
 import subprocess
 os.system("cd /home/sdn/Downloads/ryu/ryu/app")
 print("The working directory : ")
 os.system("pwd")
 print('\n')
 #insert time delay and open new terminal
 os.system('./rest_router.py')
 os.system('./gui_topology.py')
 #insert time delay and open new terminal
 os.system('sudo /opt/onos/bin/onos-service start')
 #insert time delay
 #these curl commands are apparently wrong syntax?
 os.system('curl - X POST -d '\{'address': '10.1.1.2/24'\}' http://localhost:8080/router/000056e95a9e4843)
 os.system('curl -X POST -d '\{'address': '10.2.2.2/24'\}' http://localhost:8080/router/000056e95a9e4843)
 os.system('curl -X POST -d '\{'address': '10.3.3.2/24'\}' http://localhost:8080/router/000056e95a9e4843)